Method, device and electronic equipment for detecting cross-connection of photovoltaic connection terminals

Abstract

The application provides a photovoltaic connection terminal cross-connection detection method, device and electronic equipment, and relates to the technical field of energy storage systems. The method comprises the following steps: obtaining a first converted inductor current and a first sampled inductor current; obtaining a second converted inductor current and a second sampled inductor current; if the absolute value of the difference between the first converted inductor current and the first sampled inductor current is greater than a first preset threshold value, and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is less than a second preset threshold value, it is determined that a photovoltaic panel negative terminal cross-connection has occurred; wherein the photovoltaic panel negative terminal cross-connection is that a first panel negative terminal is connected to a second photovoltaic negative equipment terminal by mistake, and a second panel negative terminal is connected to a first photovoltaic negative equipment terminal by mistake. In the technical scheme of the application, whether a cross-connection has occurred and the position of the cross-connection can be determined in time and accurately, thereby ensuring the photovoltaic power generation efficiency.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and more specifically, to a method, apparatus, and electronic device for detecting cross-connection errors of photovoltaic connection terminals. Background Technology

[0002] A photovoltaic energy storage system is a comprehensive system composed of photovoltaic modules and energy storage devices. Its core function is to capture solar energy through photovoltaic modules and convert it into electrical energy, store the electrical energy in the energy storage devices, and supply power to some loads through the energy storage devices according to the electricity demand, so as to achieve efficient energy utilization and supply-demand balance.

[0003] Generally, all photovoltaic input interfaces (photovoltaic connection terminals) are the same style. Therefore, it is easy to accidentally connect two or more photovoltaic connection terminals in a cross-connection during installation. Since the photovoltaic system can still operate after a cross-connection, workers or users may overlook the problem.

[0004] Incorrect cross-connection can lead to errors in the acquisition of photovoltaic input current, affecting the maximum power point tracking (MPPT) function of the photovoltaic system and consequently impacting energy utilization efficiency. Furthermore, incorrect cross-connection can cause mutual coupling between photovoltaic DC-DC converters, affecting their stable operation.

[0005] The current solution to the problem of incorrect cross-connection of photovoltaic (PV) terminals is to manually inspect and verify them during the PV module installation phase by staff or users. However, due to the similarity of PV modules, cables, and terminals, as well as the complex influence of the on-site environment, it is easy to miss detections.

[0006] Therefore, how to provide a method or device for detecting cross-connection errors of photovoltaic connection terminals is an urgent problem to be solved. Summary of the Invention

[0007] In order to solve or improve the technical problems that manual inspection is prone to missing detection and cannot accurately and efficiently detect cross-connection errors of photovoltaic connection terminals, one object of the present invention is to provide a method for detecting cross-connection errors of photovoltaic connection terminals.

[0008] Another object of the present invention is to provide a detection device for cross-connection errors of photovoltaic connection terminals.

[0009] Another object of the present invention is to provide an electronic device.

[0010] To achieve the above objectives, the first aspect of the present invention provides a method for detecting cross-connection errors of photovoltaic connection terminals, applied to an energy storage device. The energy storage device includes a first photovoltaic DC-DC converter and a second photovoltaic DC-DC converter. The first photovoltaic DC-DC converter is connected to a first photovoltaic positive terminal and a first photovoltaic negative terminal. The first photovoltaic positive terminal is used to connect to the positive terminal of the first end of the first photovoltaic panel. The first photovoltaic DC-DC converter includes a first step-up / step-down inductor. The second photovoltaic DC-DC converter is connected to a second photovoltaic positive terminal and a second photovoltaic negative terminal. The second photovoltaic positive terminal is used to connect to the positive terminal of the second end of the second photovoltaic panel. The second photovoltaic DC-DC converter includes a second step-up / step-down inductor.

[0011] The detection method includes: acquiring a first converted inductor current and a first sampled inductor current, wherein the first converted inductor current is obtained by converting the first input current of the first photovoltaic negative electrode terminal through a first conversion relationship, and the first sampled inductor current is the average current of the first step-up / step-down inductor during the sampling period; acquiring a second converted inductor current and a second sampled inductor current, wherein the second converted inductor current is obtained by converting the second input current of the second photovoltaic negative electrode terminal through a first conversion relationship, and the second sampled inductor current is the average current of the second step-up / step-down inductor during the sampling period; if the absolute value of the difference between the first converted inductor current and the first sampled inductor current is greater than a first preset threshold, and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is less than a second preset threshold, it is determined that a cross-connection of the photovoltaic panel negative terminals has occurred; wherein, the cross-connection of the photovoltaic panel negative terminals is that the first negative terminal of the first photovoltaic panel is mistakenly connected to the second photovoltaic negative electrode terminal, and the second negative terminal of the second photovoltaic panel is mistakenly connected to the first photovoltaic negative electrode terminal.

[0012] This invention aims to provide a method for detecting cross-connection errors in photovoltaic (PV) connection terminals. Based on a first sampled inductor current, a first converted inductor current, and a second converted inductor current, it determines whether a cross-connection error has occurred on the negative terminal of the PV panel. This detection method has several advantages. First, it can promptly and accurately determine whether a cross-connection error has occurred on the negative terminal of the PV panel and the location of the error, reducing labor intensity and the possibility of missed detections, thus improving detection efficiency and the accuracy of the results. Second, it can effectively detect cross-connection errors in PV connection terminals without increasing hardware costs, which helps control detection costs. Third, by accurately and efficiently detecting cross-connection errors in PV connection terminals, it can effectively avoid serious deviations in the acquisition of PV input current, ensuring that the maximum power point tracking function of the PV system does not fail, allowing the PV panel to operate at its optimal power generation efficiency point, which is beneficial to improving the utilization efficiency of solar energy. It can also effectively prevent unexpected electrical coupling between PV DC converters, which helps to extend the service life of related electronic components and ensure the long-term stable operation of energy storage equipment.

[0013] In some technical solutions, optionally, after determining that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, the detection method further includes: sending cross-connection error fault information to the energy storage management cloud platform, so that the energy storage management cloud platform can send cross-connection error prompt information to the user terminal based on the cross-connection error fault information, or sending cross-connection error fault information to the user terminal through short-range wireless communication.

[0014] This technical solution allows for the timely detection of fault locations, alerting or notifying staff or users to check the wiring. This design approach helps reduce labor intensity and the possibility of missed detections, thereby improving detection efficiency and the accuracy of test results.

[0015] In some technical solutions, the energy storage device may optionally include a first indicator light and a second indicator light; wherein the first indicator light is located at the terminal of the first photovoltaic negative electrode device, and the second indicator light is located at the terminal of the second photovoltaic negative electrode device; after determining that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, the detection method may further include: controlling the first indicator light and the second indicator light to illuminate or flash.

[0016] In this technical solution, by setting indicator lights, staff or users can easily and accurately determine whether there is a cross-connection error of the negative terminal of the photovoltaic panel and the location of the cross-connection error, which helps to reduce labor intensity and the possibility of missed detection.

[0017] In some technical solutions, the energy storage device may optionally include a voice prompt module; after determining that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, the detection method may also include: controlling the voice prompt module to broadcast the cross-connection error fault information.

[0018] In this technical solution, by setting up a voice prompt module, staff or users can easily and accurately determine whether there is a cross-connection error of the negative terminal of the photovoltaic panel and the location of the cross-connection error, which helps to reduce labor intensity and the possibility of missed detection.

[0019] In some technical solutions, the energy storage device may optionally include a battery module, with the output terminals of the first photovoltaic DC converter and the second photovoltaic DC converter both connected to the battery module; the detection method may further include: acquiring the first photovoltaic input voltage at the input terminal of the first photovoltaic DC converter and the battery voltage of the battery module connected to the output terminal of the first photovoltaic DC converter; determining the duty cycle of the first bridge arm of the first photovoltaic DC converter on the side closest to the first photovoltaic panel based on the ratio of the battery voltage to the first photovoltaic input voltage; and determining a first conversion relationship based on the first bridge arm duty cycle.

[0020] In this technical solution, the duty cycle of the first bridge arm is determined based on the ratio of the battery voltage to the first photovoltaic input voltage, and a first conversion relationship is determined so that the first converted inductor current can be determined based on the first input current and the first conversion relationship in subsequent steps, and the second converted inductor current can be determined based on the second input current and the first conversion relationship.

[0021] In some technical solutions, optionally, if the absolute value of the difference between the first converted inductor current and the first sampled inductor current is greater than a first preset threshold, and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is less than a second preset threshold, it is determined that a cross-connection error has occurred at the negative terminal of the photovoltaic panel. This includes: continuously acquiring the first converted inductor current and the first sampled inductor current, and continuously acquiring the second converted inductor current and the second sampled inductor current within a preset time. If the absolute value of the difference between the first converted inductor current and the first sampled inductor current is continuously greater than the first preset threshold within the preset time, and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is continuously less than the second preset threshold within the preset time, it is determined that a cross-connection error has occurred at the negative terminal of the photovoltaic panel.

[0022] In this technical solution, in addition to the two judgment conditions, a constraint of "the duration of satisfying the condition is greater than or equal to a preset time" is added, forming a composite detection logic of "dual difference judgment and time verification". This detection method can filter out interference signals with short durations, which helps to improve the accuracy of the detection results and largely avoids misjudgment.

[0023] In some technical solutions, optionally, the first preset threshold is 1A to 3A; and / or the second preset threshold is 1A to 3A; and / or the preset time is 1s to 3s.

[0024] In this technical solution, by limiting the range of preset threshold values ​​(first preset threshold or second preset threshold), firstly, the preset threshold is avoided from being too small, so that numerical sampling and numerical calculation (conversion) can be within a certain error range, effectively compatibility with the inherent errors of numerical sampling and current conversion processes in photovoltaic energy storage systems; secondly, the preset threshold is avoided from being too large, which helps to ensure detection sensitivity, thereby accurately detecting whether there are incorrect connection methods for photovoltaic cross-connection.

[0025] By limiting the range of preset time values, firstly, it avoids setting the preset time too small, ensuring that short-duration interference signals can be filtered out, thereby improving the accuracy of the detection results; secondly, it avoids setting the preset time too large, which is conducive to improving detection efficiency.

[0026] In some technical solutions, optionally, there are multiple second photovoltaic DC converters and multiple second photovoltaic panels. The second photovoltaic positive terminal of each second photovoltaic DC converter is connected to the positive terminal of the second panel of a corresponding second photovoltaic panel. Obtaining the second calculated inductor current and the second sampled inductor current includes: obtaining the second calculated inductor current and the second sampled inductor current corresponding to each second photovoltaic DC converter; if the absolute value of the difference between the first calculated inductor current and the first sampled inductor current is greater than a first preset threshold, and the absolute value of the difference between the second calculated inductor current and the first sampled inductor current is less than the second preset threshold, determining that a cross-connection of the negative terminal of the photovoltaic panel has occurred includes: sequentially taking each second photovoltaic DC converter as the current second photovoltaic DC converter; if the absolute value of the difference between the first calculated inductor current and the first sampled inductor current is greater than the first preset threshold, and the absolute value of the difference between the second calculated inductor current and the first sampled inductor current corresponding to the current second photovoltaic DC converter is less than the second preset threshold, determining that a cross-connection of the negative terminal of the photovoltaic panel has occurred between the first photovoltaic DC converter and the current second photovoltaic DC converter.

[0027] In this technical solution, the first converted inductor current is compared with the first sampled inductor current to determine whether a cross-connection error has occurred; each second converted inductor current is compared with the first sampled inductor current to simultaneously determine whether a cross-connection error has occurred and to locate the cross-connection error. This design allows staff or users to quickly and accurately determine whether a cross-connection error has occurred on the negative terminal of the photovoltaic panel and its location, thus reducing labor intensity and the possibility of missed detections.

[0028] A second aspect of the present invention provides a detection device for cross-connection errors of photovoltaic connection terminals, comprising: a first current acquisition unit for acquiring a first converted inductor current and a first sampled inductor current, wherein the first converted inductor current is obtained by converting a first input current of a first photovoltaic negative electrode terminal through a first conversion relationship, and the first sampled inductor current is the average current of a first step-up / step-down inductor during the sampling period; and a second current acquisition unit for acquiring a second converted inductor current and a second sampled inductor current, wherein the second converted inductor current is obtained by converting a second input current of a second photovoltaic negative electrode terminal through the first conversion relationship. The second sampling inductor current is the average current of the second step-up / step-down inductor during the sampling period; the cross-connection determination unit is used to determine that a cross-connection of the negative terminal of the photovoltaic panel has occurred if the absolute value of the difference between the first converted inductor current and the first sampling inductor current is greater than a first preset threshold, and the absolute value of the difference between the second converted inductor current and the first sampling inductor current is less than a second preset threshold; wherein, the cross-connection of the negative terminal of the photovoltaic panel is when the first negative terminal of the first photovoltaic panel is mistakenly connected to the terminal of the second photovoltaic negative electrode device, and the second negative terminal of the second photovoltaic panel is mistakenly connected to the terminal of the first photovoltaic negative electrode device.

[0029] This invention aims to provide a detection device for cross-connection errors in photovoltaic (PV) terminals. Based on a first sampling inductor current, a first converted inductor current, and a second converted inductor current, it determines whether a cross-connection error has occurred on the negative terminal of the PV panel. This detection method has several advantages. First, it can promptly and accurately determine whether a cross-connection error has occurred on the negative terminal of the PV panel and the location of the error, reducing labor intensity and the possibility of missed detections, thus improving detection efficiency and the accuracy of the results. Second, it can effectively detect cross-connection errors in PV terminals without increasing hardware costs, which helps control detection costs. Third, by accurately and efficiently detecting cross-connection errors in PV terminals, it can effectively avoid serious deviations in the acquisition of PV input current, ensuring that the maximum power point tracking function of the PV system does not fail, allowing the PV panel to operate at its optimal power generation efficiency point, which is beneficial to improving the utilization efficiency of solar energy. It can also effectively prevent unexpected electrical coupling between PV DC converters, which helps to extend the service life of related electronic components and ensure the long-term stable operation of energy storage equipment.

[0030] A third aspect of the present invention provides an electronic device, comprising: a memory and a processor, wherein the memory stores a program or instructions executable on the processor, and the processor, when executing the program or instructions, implements the steps of the method for detecting cross-connection errors of photovoltaic connection terminals in any of the above-described technical solutions. The electronic device possesses the beneficial effects of any of the above-described technical solutions, which will not be elaborated further here.

[0031] Additional aspects and advantages of the technical solutions of the present invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0032] Figure 1 A circuit diagram of a photovoltaic energy storage system according to an embodiment of the present invention is shown;

[0033] Figure 2 A circuit diagram of a photovoltaic energy storage system according to another embodiment of the present invention is shown;

[0034] Figure 3 A structural block diagram of a photovoltaic energy storage system according to an embodiment of the present invention is shown;

[0035] Figure 4 A structural block diagram of a photovoltaic energy storage system according to another embodiment of the present invention is shown;

[0036] Figure 5 A structural block diagram of a photovoltaic energy storage system according to another embodiment of the present invention is shown;

[0037] Figure 6A structural block diagram of a photovoltaic energy storage system according to another embodiment of the present invention is shown;

[0038] Figure 7 A flowchart of a method for detecting cross-connection errors of photovoltaic connection terminals according to an embodiment of the present invention is shown;

[0039] Figure 8 A flowchart is shown for a method for detecting incorrect cross-connection of photovoltaic connection terminals according to another embodiment of the present invention;

[0040] Figure 9 A flowchart is shown for a method for detecting incorrect cross-connection of photovoltaic connection terminals according to another embodiment of the present invention;

[0041] Figure 10 A structural block diagram of an energy storage device according to an embodiment of the present invention is shown;

[0042] Figure 11 A flowchart is shown for a method for detecting incorrect cross-connection of photovoltaic connection terminals according to another embodiment of the present invention;

[0043] Figure 12 A flowchart is shown for a method for detecting incorrect cross-connection of photovoltaic connection terminals according to another embodiment of the present invention;

[0044] Figure 13 A flowchart is shown for a method for detecting incorrect cross-connection of photovoltaic connection terminals according to another embodiment of the present invention;

[0045] Figure 14 A flowchart is shown for a method for detecting incorrect cross-connection of photovoltaic connection terminals according to another embodiment of the present invention;

[0046] Figure 15 A structural block diagram of a detection device for cross-connection errors of photovoltaic connection terminals according to an embodiment of the present invention is shown;

[0047] Figure 16 A structural block diagram of an electronic device according to an embodiment of the present invention is shown.

[0048] in, Figures 1 to 16 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0049] 100: Photovoltaic energy storage system; 110: Energy storage device; 111: First photovoltaic DC-DC converter; 1111: First photovoltaic positive electrode terminal; 1112: First photovoltaic negative electrode terminal; 1113: First step-up / step-down inductor; 112: Second photovoltaic DC-DC converter; 1121: Second photovoltaic positive electrode terminal; 1122: Second photovoltaic negative electrode terminal; 1123: Second step-up / step-down inductor; 114: Battery module; 1151: First indicator light; 1152: Second indicator light ; 116: Voice prompt module; 120: First photovoltaic panel; 121: Positive terminal of the first panel; 122: Negative terminal of the first panel; 130: Second photovoltaic panel; 131: Positive terminal of the second panel; 132: Negative terminal of the second panel; 300: Detection device for cross-connection error of photovoltaic connection terminals; 310: First current acquisition unit; 320: Second current acquisition unit; 330: Cross-connection error judgment unit; 400: Electronic device; 410: Memory; 420: Processor. Detailed Implementation

[0050] To better understand the above-described objectives, features, and advantages of the embodiments of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0051] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, embodiments of the invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0052] As the global energy structure shifts towards cleaner and lower-carbon energy, new energy technologies, especially photovoltaic power generation technology, have developed rapidly. Photovoltaic energy storage systems, as the core equipment for achieving efficient storage and flexible application of photovoltaic power generation, have been widely used in scenarios such as homes, industrial and commercial facilities, and large power plants.

[0053] A photovoltaic energy storage system is a comprehensive system composed of photovoltaic modules and energy storage devices. Its core function is to capture solar energy through photovoltaic modules and convert it into electrical energy, store the electrical energy in the energy storage devices, and supply power to some loads through the energy storage devices according to the electricity demand, so as to achieve efficient energy utilization and supply-demand balance.

[0054] In current mainstream photovoltaic (PV) energy storage system architectures, connecting multiple PV modules in parallel to the same energy storage device has become a common design approach to increase total energy collection. However, due to the high degree of uniformity in structure and appearance of the input interfaces, cables, and terminals of various PV modules, workers or users are prone to visual confusion or operational negligence during on-site installation, leading to incorrect cross-connection of terminals between two or more PV modules. Specifically, the output terminal of one PV module may be incorrectly connected to the input terminal of another PV converter instead of the corresponding input terminal of the PV DC-DC converter as designed.

[0055] Energy storage devices, also known as integrated energy storage units, are a type of integrated unit that combines energy storage batteries and inverters. Energy storage devices can be consumer-grade, including portable outdoor energy storage devices, home energy storage devices, and balcony photovoltaic energy storage devices. Portable outdoor energy storage devices are designed for mobile scenarios such as camping and road trips, providing lightweight, plug-and-play low- to medium-power power supply. Home energy storage devices are geared towards users with detached houses (usually equipped with rooftop photovoltaics), deeply integrating photovoltaic systems to store surplus electricity for home energy management (improving self-consumption rate) and providing long-term emergency backup power. Balcony photovoltaic energy storage devices are designed for urban apartment users (with limited space / budget), achieving "self-consumption with surplus electricity fed into the grid" by installing micro-photovoltaic modules on the balcony, primarily used to reduce daily electricity bills.

[0056] Cross-connection errors do not cause the photovoltaic energy storage system to shut down directly; the system can still maintain basic operation. This makes it difficult to detect and troubleshoot cross-connection errors immediately after installation.

[0057] The persistent problem of cross-connection errors leads to two major technical defects: First, cross-connection errors cause serious deviations in the acquisition of photovoltaic input current. The accuracy of current acquisition is the core basis for the photovoltaic system to achieve maximum power point tracking (MPPT). Incorrect current acquisition will directly cause the MPPT function to fail, preventing the photovoltaic module from operating at its optimal power generation efficiency point and significantly reducing the utilization efficiency of solar energy. Second, as a key conversion unit connecting photovoltaic modules and energy storage devices, the photovoltaic DC-DC converter is designed to achieve stable operation based on the electrical characteristics of a single photovoltaic module. Cross-connection errors can lead to unexpected electrical coupling between multiple photovoltaic DC-DC converters, disrupting the current closed-loop control and voltage regulation balance inside the photovoltaic DC-DC converter. This can cause problems such as output fluctuations, abnormal heating, and even component damage, seriously threatening the long-term stable operation of the photovoltaic DC-DC converter.

[0058] The common solution to the problem of incorrect cross-connection of photovoltaic (PV) terminals in existing technologies is to manually inspect and verify the connections during the PV module installation phase (checking wiring labels and verifying terminal connections one by one). However, in practical applications, on the one hand, PV modules, cables, and terminals are highly similar and lack distinctive features, easily leading to visual misjudgment; on the other hand, the on-site installation environment often has complex factors such as narrow spaces and insufficient lighting, further increasing the difficulty of manual verification and resulting in a high rate of missed detections, failing to fundamentally solve the system hazards caused by incorrect cross-connection.

[0059] Therefore, how to overcome the shortcomings of manual inspection in existing technologies that are prone to omissions, and achieve accurate and efficient detection of cross-connection errors in photovoltaic connection terminals, is an urgent problem to be solved.

[0060] This invention aims to provide a method, device, and electronic device for detecting cross-connection errors in photovoltaic (PV) connection terminals. Based on a first sampled inductor current (local sampled inductor current), a first converted inductor current (local converted inductor current), and a second converted inductor current (other converted inductor current), it determines whether a cross-connection error has occurred on the negative terminal of the PV panel. This detection method has several advantages. First, it can promptly and accurately determine whether a cross-connection error has occurred on the negative terminal of the PV panel and the location of the error, reducing labor intensity and the possibility of missed detections, thus improving detection efficiency and the accuracy of the results. Second, it can effectively detect cross-connection errors in PV connection terminals without increasing hardware costs, which helps control detection costs. Third, by accurately and efficiently detecting cross-connection errors in PV connection terminals, it can effectively avoid serious deviations in the acquisition of PV input current, ensuring that the maximum power point tracking function of the PV system does not fail, allowing the PV panel to operate at its optimal power generation efficiency point, which is beneficial for improving the utilization efficiency of solar energy. It can also effectively avoid unexpected electrical coupling between PV DC converters, which helps extend the service life of related electronic components and ensures the long-term stable operation of energy storage equipment.

[0061] The following reference Figures 1 to 16 This invention describes a method, apparatus, and electronic device for detecting cross-connection errors of photovoltaic connection terminals, provided by some embodiments of the invention.

[0062] In one embodiment of the present invention, the photovoltaic energy storage system 100 includes an energy storage device 110 and a plurality of photovoltaic panels. The plurality of photovoltaic panels are connected to the energy storage device 110 in parallel.

[0063] Taking two photovoltaic panels as an example, the two photovoltaic panels are the first photovoltaic panel 120 and the second photovoltaic panel 130.

[0064] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the photovoltaic energy storage system 100 includes an energy storage device 110, a first photovoltaic panel 120, and a second photovoltaic panel 130. The energy storage device 110 is connected to the first photovoltaic panel 120, and the energy storage device 110 is also connected to the second photovoltaic panel 130.

[0065] The first photovoltaic panel 120 and the second photovoltaic panel 130 serve as photovoltaic modules to convert solar energy into electrical energy. The energy storage device 110 stores this electrical energy and supplies power to some loads according to electricity demand.

[0066] It should be noted that when there are three or more photovoltaic panels, there are multiple first photovoltaic panels 120 and / or multiple second photovoltaic panels 130.

[0067] In one embodiment of the present invention, the energy storage device 110 includes a plurality of photovoltaic DC-DC converters and an energy storage battery (battery module 114). Each of the plurality of photovoltaic DC-DC converters is electrically connected to the energy storage battery. Each photovoltaic DC-DC converter is electrically connected to a corresponding photovoltaic panel.

[0068] Taking two photovoltaic DC converters as an example, the two photovoltaic DC converters are the first photovoltaic DC converter 111 and the second photovoltaic DC converter 112.

[0069] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the energy storage device 110 includes a first photovoltaic DC converter 111 and a second photovoltaic DC converter 112.

[0070] The first photovoltaic DC converter 111 is connected to a first photovoltaic positive terminal 1111 and a first photovoltaic negative terminal 1112. The first photovoltaic positive terminal 1111 is used to connect to the first positive terminal 121 of the first photovoltaic panel 120. The first photovoltaic DC converter 111 includes a first step-up / step-down inductor 1113.

[0071] The second photovoltaic DC converter 112 is connected to a second photovoltaic positive device terminal 1121 and a second photovoltaic negative device terminal 1122. The second photovoltaic positive device terminal 1121 is used to connect to the second positive terminal 131 of the second photovoltaic panel 130. The second photovoltaic DC converter 112 includes a second step-up / step-down inductor 1123.

[0072] It should be noted that the first photovoltaic DC converter 111 and the second photovoltaic DC converter 112 are used to regulate the voltage of the electrical energy output from the photovoltaic panel. When there are three or more photovoltaic DC converters, there are multiple first photovoltaic DC converters 111 and / or multiple second photovoltaic DC converters 112.

[0073] When multiple photovoltaic panels are connected in parallel to the same energy storage device 110, there may be cases of incorrect cross-connection of photovoltaic connection terminals.

[0074] Taking the first photovoltaic panel 120, the second photovoltaic panel 130, the first photovoltaic DC converter 111, and the second photovoltaic DC converter 112 as an example:

[0075] like Figure 3 As shown, when the photovoltaic panel and the photovoltaic DC converter are normally connected, the first positive terminal 121 of the first photovoltaic panel 120 is connected to the first photovoltaic positive terminal 1111 of the first photovoltaic DC converter 111, the first negative terminal 122 of the first photovoltaic panel 120 is connected to the first photovoltaic negative terminal 1112 of the first photovoltaic DC converter 111, the second positive terminal 131 of the second photovoltaic panel 130 is connected to the second photovoltaic positive terminal 1121 of the second photovoltaic DC converter 112, and the second negative terminal 132 of the second photovoltaic panel 130 is connected to the second photovoltaic negative terminal 1122 of the second photovoltaic DC converter 112.

[0076] like Figure 4 As shown, in the case of incorrect cross-connection of photovoltaic connection terminals, the first positive terminal 121 of the first photovoltaic panel 120 is connected to the first photovoltaic positive terminal 1111 of the first photovoltaic DC converter 111, the first negative terminal 122 of the first photovoltaic panel 120 is incorrectly connected to the second photovoltaic negative terminal 1122 of the second photovoltaic DC converter 112, the second positive terminal 131 of the second photovoltaic panel 130 is connected to the second photovoltaic positive terminal 1121 of the second photovoltaic DC converter 112, and the second negative terminal 132 of the second photovoltaic panel 130 is incorrectly connected to the first photovoltaic negative terminal 1112 of the first photovoltaic DC converter 111.

[0077] Figure 2This is a circuit diagram of a photovoltaic energy storage system 100 when the photovoltaic panel and the corresponding photovoltaic DC converter are normally connected. Taking the first photovoltaic panel 120 and the first photovoltaic DC converter 111 as an example, when the photovoltaic panel and the corresponding photovoltaic DC converter are normally connected, the current path is: "first positive terminal 121 of the first photovoltaic panel 120 → first positive terminal 1111 of the first photovoltaic DC converter 111 → internal circuit of the first photovoltaic DC converter 111 → first negative terminal 1112 of the first photovoltaic DC converter 111 → first negative terminal 122 of the first photovoltaic panel 120".

[0078] Figure 1 This is a circuit diagram of a photovoltaic energy storage system 100 when the photovoltaic connection terminals are incorrectly crossed. Taking the first photovoltaic panel 120 as an example, in the case of incorrect connection of the photovoltaic connection terminals, the current path is as follows: "first positive terminal 121 of the first photovoltaic panel 120 → first positive terminal 1111 of the first photovoltaic DC converter 111 → internal circuit of the first photovoltaic DC converter 111 → first negative terminal 1112 of the first photovoltaic DC converter 111 → second negative terminal 1122 of the second photovoltaic DC converter 112 → first negative terminal 122 of the first photovoltaic panel 120".

[0079] It should be noted that multiple photovoltaic DC converters are connected to a common ground, therefore, the negative terminals (photovoltaic negative electrode terminals) of multiple photovoltaic DC converters are interconnected.

[0080] In the technical solution of this invention, by setting the sampling point of the photovoltaic input current at the negative terminal (photovoltaic negative electrode terminal) of the photovoltaic DC converter, under the dual conditions of incorrect cross-connection of photovoltaic connection terminals and multiple photovoltaic DC converters sharing a common ground, the sampled current is naturally the input current of the photovoltaic panel that is incorrectly cross-connected with this photovoltaic DC converter. This detection method is beneficial for accurately and efficiently detecting incorrect cross-connection of photovoltaics.

[0081] In some embodiments, the energy storage device 110 may optionally include an EMS module (Energy Management System). The EMS module is used for communication connection with the energy storage management cloud platform and / or user terminal.

[0082] In one specific embodiment, if a cross-connection error is detected at the negative terminal of the photovoltaic panel, the energy storage device 110 sends cross-connection error fault information to the energy storage management cloud platform via the EMS module. Based on the cross-connection error fault information, the energy storage management cloud platform sends a reminder message (cross-connection error alert message) to the user terminal.

[0083] In one specific embodiment, if it is determined that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, the energy storage device 110 sends the cross-connection error fault information to the user terminal through the EMS module.

[0084] It should be noted that the user terminal can be a mobile phone or a laptop computer, etc.

[0085] In one embodiment of the present invention, the method for detecting cross-connection errors of photovoltaic connection terminals is applied to energy storage device 110.

[0086] like Figure 7 As shown, the detection method for incorrect cross-connection of photovoltaic connection terminals includes:

[0087] S202, obtain the first converted inductor current and the first sampled inductor current. The first converted inductor current is obtained by converting the first input current of the first photovoltaic negative electrode terminal through the first conversion relationship. The first sampled inductor current is the average current of the first step-up / step-down inductor during the sampling period.

[0088] It should be noted that if the sampling point of the photovoltaic input current is set at the negative terminal of the photovoltaic panel (the negative terminal of the panel), regardless of whether there is a cross-connection or not, the sampling current at the negative terminal of the photovoltaic panel will always be the "output current of this photovoltaic circuit", and it will not be able to report wiring errors.

[0089] In non-isolated photovoltaic (PV) systems, multiple PV DC-DC converters are grounded together, and therefore, their negative terminals (PV negative electrode terminals) are interconnected. By placing the PV input current sampling point at the negative terminal (PV negative electrode terminal) of the PV DC-DC converter, the input current of the PV panel that is incorrectly connected to this PV DC-DC converter can be sampled.

[0090] By setting the sampling point of the photovoltaic input current at the negative terminal (photovoltaic negative electrode terminal) of the photovoltaic DC converter, under the dual conditions of incorrect cross-connection of photovoltaic terminals and multiple photovoltaic DC converters sharing a common ground, the sampled current is naturally the input current of the photovoltaic panel that is incorrectly cross-connected with this photovoltaic DC converter. This detection method is beneficial for accurately and efficiently detecting incorrect cross-connection of photovoltaics.

[0091] By acquiring the first sampled inductor current and the first converted inductor current, it is convenient to compare the first sampled inductor current and the first converted inductor current in subsequent steps to determine whether a cross-connection of the negative terminal of the photovoltaic panel has occurred.

[0092] It should be noted that the first sampling inductor current is used as the sampling inductor current of this channel, and the first converted inductor current is used as the converted inductor current of this channel.

[0093] Optionally, the average current of the first buck-boost inductor during the sampling period is used as the first sampling inductor current. The first converted inductor current is determined based on the first input current and the first conversion relationship.

[0094] In one specific embodiment, the first converted inductor current is calculated by multiplying the sampled input current of the first photovoltaic panel (the first input current of the first photovoltaic negative electrode device terminal) with the output duty cycle of the first photovoltaic DC converter.

[0095] Once the photovoltaic DC / DC (Direct Current to Direct Current) converter is operating stably, there is a corresponding conversion relationship between the inductor current and the input current.

[0096] Taking a four-switch photovoltaic converter (a specific form of photovoltaic DC converter) as an example, the input current is multiplied by the corresponding output duty cycle (bridge arm duty cycle) to calculate the converted inductor current. Theoretically, the converted inductor current is equal to the average value of the sampled inductor current over the same period.

[0097] S204, obtain the second converted inductor current and the second sampled inductor current. The second converted inductor current is obtained by converting the second input current of the second photovoltaic negative electrode terminal through the first conversion relationship. The second sampled inductor current is the average current of the second step-up / step-down inductor during the sampling period.

[0098] It should be noted that the second sampling inductor current is used as the other sampling inductor current, and the second converted inductor current is also used as the other converted inductor current. When there are multiple second photovoltaic DC converters and multiple second photovoltaic panels, the second converted inductor current and the second sampling inductor current corresponding to each second photovoltaic DC converter are obtained. In subsequent steps, each second converted inductor current is compared with the first sampling inductor current to check for any cross-connection errors and their locations.

[0099] Optionally, the average current of the second buck-boost inductor during the sampling period is used as the second sampling inductor current. The second converted inductor current is determined based on the second input current and the second conversion relationship.

[0100] The second converted inductor current is calculated by multiplying the sampled input current of the second photovoltaic panel (the second input current of the second photovoltaic negative electrode device terminal) with the duty cycle of the first bridge arm of the first photovoltaic DC converter.

[0101] S206, if the absolute value of the difference between the first converted inductor current and the first sampled inductor current is greater than the first preset threshold, and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is less than the second preset threshold, it is determined that a cross-connection of the negative terminals of the photovoltaic panel has occurred; wherein, the cross-connection of the negative terminals of the photovoltaic panel is that the first negative terminal of the first photovoltaic panel is mistakenly connected to the second negative terminal of the photovoltaic device, and the second negative terminal of the second photovoltaic panel is mistakenly connected to the first negative terminal of the photovoltaic device.

[0102] The converted inductor current (first converted inductor current) of this channel is compared with the sampled inductor current (first sampled inductor current) of this channel. The comparison result is used as one of the judgment conditions to determine whether cross-connection has occurred. Considering the actual sampling and calculation deviations, a first preset threshold is set. If the absolute value of the difference between the converted inductor current and the sampled inductor current of this channel is greater than the first preset threshold, it is initially judged that cross-connection may exist.

[0103] The comparison between the converted inductor current of the other path (second converted inductor current) and the sampled inductor current of this path (first sampled inductor current) is used as another judgment condition to determine whether cross-connection has occurred and to investigate the location of cross-connection errors. Considering the actual sampling and calculation deviations, a second preset threshold is set. If the absolute value of the difference between the converted inductor current of the other path and the sampled inductor current of this path is less than the second preset threshold, it is determined that cross-connection errors exist.

[0104] This invention aims to provide a method for detecting cross-connection errors in photovoltaic (PV) connection terminals. Based on a first sampled inductor current (local sampled inductor current), a first converted inductor current (local converted inductor current), and a second converted inductor current (other converted inductor current), it determines whether a cross-connection error has occurred on the negative terminal of the PV panel. This detection method has several advantages. First, it can promptly and accurately determine whether a cross-connection error has occurred on the negative terminal of the PV panel and the location of the error, reducing labor intensity and the possibility of missed detections, thus improving detection efficiency and the accuracy of the results. Second, it can effectively detect cross-connection errors in PV connection terminals without increasing hardware costs, which helps control detection costs. Third, by accurately and efficiently detecting cross-connection errors in PV connection terminals, it can effectively avoid serious deviations in the acquisition of PV input current, ensuring that the maximum power point tracking function of the PV system does not fail, allowing the PV panel to operate at its optimal power generation efficiency point, which is beneficial for improving the utilization efficiency of solar energy. It can also effectively prevent unexpected electrical coupling between PV DC converters, which helps extend the service life of related electronic components and ensures the long-term stable operation of energy storage equipment.

[0105] In some embodiments, optionally, such as Figure 9As shown, after determining that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, the detection method for cross-connection error at the photovoltaic connection terminals also includes:

[0106] S2081, send cross-connection fault information to the energy storage management cloud platform so that the energy storage management cloud platform can send cross-connection fault prompt information to the user terminal based on the cross-connection fault information, or send cross-connection fault information to the user terminal through short-range wireless communication.

[0107] In the event of a cross-connection error on the negative terminal of a photovoltaic panel, the EMS module of the energy storage device is used to send cross-connection error fault information to the energy storage management cloud platform, or to send cross-connection error fault information to the user terminal via short-range wireless communication.

[0108] In the event of a cross-connection error on the negative terminal of a photovoltaic panel, the energy storage management cloud platform receives cross-connection error fault information from the EMS module. Based on this information, the energy storage management cloud platform sends a cross-connection error alert to the user terminal.

[0109] In the event of a cross-connection error on the negative terminal of a photovoltaic panel, the EMS module of the energy storage device sends cross-connection fault information to the user terminal. The user terminal receives the cross-connection fault information from the EMS module.

[0110] By promptly identifying the location of faults and alerting or notifying staff or users to check the wiring, this design approach helps reduce labor intensity and the possibility of missed detections, thereby improving testing efficiency and the accuracy of test results.

[0111] In some embodiments, the cross-connection fault information may optionally include the location information of the cross-connection, the time point in which the cross-connection occurred, and the duration of the cross-connection.

[0112] In some embodiments, optionally, such as Figure 10 As shown, the energy storage device 110 also includes a first indicator light 1151 and a second indicator light 1152. The first indicator light 1151 is located at the terminal 1112 of the first photovoltaic negative electrode device, and the second indicator light 1152 is located at the terminal 1122 of the second photovoltaic negative electrode device.

[0113] In one specific embodiment, the first indicator light 1151 is located on or near the first photovoltaic negative electrode device terminal 1112. The second indicator light 1152 is located on or near the second photovoltaic negative electrode device terminal 1122.

[0114] In some embodiments, optionally, such as Figure 11As shown, after determining that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, the detection method for cross-connection error at the photovoltaic connection terminals also includes:

[0115] S2082 controls the first and second indicator lights to illuminate or flash.

[0116] It should be noted that the color and flashing frequency of the first indicator light, as well as the color and flashing frequency of the second indicator light, can be flexibly set according to actual needs.

[0117] By setting indicator lights, staff or users can quickly and accurately determine whether there is a cross-connection error of the negative terminal of the photovoltaic panel and the location of the cross-connection error, which helps to reduce labor intensity and the possibility of missed detection.

[0118] In some embodiments, optionally, such as Figure 10 As shown, the energy storage device 110 also includes a voice prompt module 116. The voice prompt module 116 is used to broadcast cross-connection fault information.

[0119] In some embodiments, optionally, such as Figure 12 As shown, after determining that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, the detection method for cross-connection error at the photovoltaic connection terminals also includes:

[0120] S2083 controls the voice prompt module to broadcast cross-connection fault information.

[0121] It should be noted that the volume and number of times the voice prompt module is played can be flexibly set according to actual needs.

[0122] By setting up a voice prompt module, staff or users can quickly and accurately determine whether there is a cross-connection error of the negative terminal of the photovoltaic panel and the location of the cross-connection error, which helps to reduce labor intensity and the possibility of missed detection.

[0123] In some embodiments, optionally, such as Figure 1 and Figure 2 As shown, the energy storage device 110 also includes a battery module 114. The output terminals of the first photovoltaic DC-DC converter 111 and the second photovoltaic DC-DC converter 112 are both connected to the battery module 114. In other words, the first photovoltaic DC-DC converter 111 and the second photovoltaic DC-DC converter 112 are connected to the same battery module 114 in parallel.

[0124] like Figure 13 As shown, the detection method for incorrect cross-connection of photovoltaic connection terminals also includes:

[0125] S2011, obtain the first photovoltaic input voltage at the input terminal of the first photovoltaic DC converter, and the battery voltage of the battery module connected to the output terminal of the first photovoltaic DC converter.

[0126] The energy storage device includes a first voltage sensor, which is located at the input terminal of a first photovoltaic DC-DC converter and is used to obtain the first photovoltaic input voltage at the input terminal of the first photovoltaic DC-DC converter.

[0127] The energy storage device also includes a second voltage sensor, which is located in the battery module and is used to obtain the battery voltage of the battery module.

[0128] S2012, Based on the ratio of battery voltage to first photovoltaic input voltage, determine the duty cycle of the first bridge arm of the first photovoltaic DC converter on the side closest to the first photovoltaic panel.

[0129] S2013, determine the first conversion relationship based on the duty cycle of the first bridge arm.

[0130] The first converted inductor current is determined based on the first input current and the first conversion relationship.

[0131] The first converted inductor current is calculated by multiplying the sampled input current of the first photovoltaic panel (the first input current of the first photovoltaic negative electrode device terminal) with the output duty cycle of the first photovoltaic DC converter.

[0132] The converted inductor current of this path is compared with the sampled inductor current of this path. The comparison result is used as one of the judgment conditions to determine whether cross-connection has occurred.

[0133] In photovoltaic DC-DC converters, the duty cycle of the first bridge arm is a core parameter describing the operating state of the internal switching transistors. Specifically, it refers to the ratio of the on-time of the switching transistor in one working cycle to the total time of the entire cycle, usually expressed as a percentage or a decimal.

[0134] In some embodiments, the minimum value between the first ratio and 1 may be used as the duty cycle of the first arm of the first photovoltaic DC-DC converter. The first ratio is the ratio of the battery voltage to the first photovoltaic input voltage.

[0135] By using the minimum value between the first ratio and 1 as the duty cycle of the first arm of the first photovoltaic DC converter, the duty cycle of the first arm can be controlled within a safe range between 0 and 1, which helps to ensure the accuracy of the inductor current conversion.

[0136] In some embodiments, optionally, such as Figure 14 As shown, if the absolute value of the difference between the first converted inductor current and the first sampled inductor current is greater than a first preset threshold, and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is less than a second preset threshold, it is determined that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, including:

[0137] S2064, within a preset time period, continuously acquire the first converted inductor current and the first sampled inductor current, and continuously acquire the second converted inductor current and the second sampled inductor current. If the absolute value of the difference between the first converted inductor current and the first sampled inductor current is continuously greater than the first preset threshold within the preset time period, and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is continuously less than the second preset threshold within the preset time period, it is determined that a cross-connection error has occurred at the negative terminal of the photovoltaic panel.

[0138] In addition to the two judgment conditions, a third judgment condition is added: whether the duration of satisfying the condition is greater than or equal to the preset time.

[0139] If the first and second judgment conditions are met, but the third judgment condition is not met (the duration is less than the preset time), it may be due to a momentary current fluctuation that causes the conditions to be met briefly before returning to normal. This is judged as an "interference signal" and no fault alarm is triggered (the EMS module does not send cross-connection fault information).

[0140] If all three conditions are met, it is determined that a cross-connection error has occurred on the negative terminal of the photovoltaic panel. The EMS module sends a cross-connection error fault message to remind or notify staff or users to check the wiring.

[0141] Based on the two judgment conditions, an additional constraint is added: "the duration of satisfying the condition is greater than or equal to a preset time," forming a composite detection logic of "dual difference judgment and time verification." This detection method can filter out short-duration interference signals, which helps improve the accuracy of the detection results and largely avoids misjudgments.

[0142] In some embodiments, the first preset threshold may be 1A to 3A.

[0143] By limiting the range of the first preset threshold, firstly, it avoids the first preset threshold being too small, so that numerical sampling and numerical calculation (conversion) can be within a certain error range, effectively compatibility with the inherent errors in the numerical sampling and current conversion process in the photovoltaic energy storage system; secondly, it avoids the first preset threshold being too large, which helps to ensure detection sensitivity, thereby accurately detecting whether there is cross-connection error of photovoltaic connection terminals.

[0144] In one specific embodiment, the first preset threshold is 1A.

[0145] In one specific embodiment, the first preset threshold is 1.5A.

[0146] In one specific embodiment, the first preset threshold is 2A.

[0147] In one specific embodiment, the first preset threshold is 2.5A.

[0148] In one specific embodiment, the first preset threshold is 3A.

[0149] In some embodiments, the second preset threshold may optionally be 1A to 3A.

[0150] By limiting the range of the second preset threshold, firstly, the second preset threshold is not too small, so that numerical sampling and numerical calculation (conversion) can be within a certain error range, effectively compatibility with the inherent errors in the numerical sampling and current conversion process in the photovoltaic energy storage system; secondly, the second preset threshold is not too large, which helps to ensure detection sensitivity, thereby accurately detecting whether there is cross-connection error of photovoltaic connection terminals.

[0151] In one specific embodiment, the second preset threshold is 1A.

[0152] In one specific embodiment, the second preset threshold is 1.5A.

[0153] In one specific embodiment, the second preset threshold is 2A.

[0154] In one specific embodiment, the second preset threshold is 2.5A.

[0155] In one specific embodiment, the second preset threshold is 3A.

[0156] In some embodiments, the preset time is optionally 1 to 3 seconds.

[0157] By limiting the range of preset time values, firstly, it avoids setting the preset time too small, ensuring that short-duration interference signals can be filtered out, thereby improving the accuracy of the detection results; secondly, it avoids setting the preset time too large, which is conducive to improving detection efficiency.

[0158] In one specific embodiment, the preset time is 1 second.

[0159] In one specific embodiment, the preset time is 1.5s.

[0160] In one specific embodiment, the preset time is 2 seconds.

[0161] In one specific embodiment, the preset time is 2.5 seconds.

[0162] In one specific embodiment, the preset time is 3 seconds.

[0163] In some embodiments, optionally, two photovoltaic modules (two photovoltaic panels) and two photovoltaic DC-DC converters are used as an example, wherein the two photovoltaic modules are a first photovoltaic module (first photovoltaic panel, denoted as PV1) and a second photovoltaic module (second photovoltaic panel, denoted as PV2); the two photovoltaic DC-DC converters are a first photovoltaic DC-DC converter and a second photovoltaic DC-DC converter. The first photovoltaic module is correspondingly configured with the first photovoltaic DC-DC converter, and the second photovoltaic module is correspondingly configured with the second photovoltaic DC-DC converter.

[0164] In the event of a cross-connection error of the photovoltaic connection terminals, the positive terminal of the first end of the first photovoltaic panel is connected to the positive terminal of the first photovoltaic DC converter, the negative terminal of the first end of the first photovoltaic panel is mistakenly connected to the negative terminal of the second photovoltaic DC converter, the positive terminal of the second end of the second photovoltaic panel is connected to the positive terminal of the second photovoltaic DC converter, and the negative terminal of the second end of the second photovoltaic panel is mistakenly connected to the negative terminal of the first photovoltaic DC converter.

[0165] The negative terminal input current of the first photovoltaic DC converter is sampled and used as the sampling input current of the first photovoltaic module, denoted as I. pv1 The negative terminal input current of the second photovoltaic DC converter is sampled and used as the sampling input current of the second photovoltaic module, denoted as I. pv2 .

[0166] Obtain the input voltage of the first photovoltaic module (the input voltage of the first photovoltaic panel), denoted as U. pv1 Obtain the input voltage of the second photovoltaic module (the input voltage of the second photovoltaic panel), denoted as U. pv2 Obtain the battery voltage of the energy storage device (the battery voltage is common, so the basic values ​​are equal), denoted as U. bat .

[0167] It should be noted that "bat" or "Bat" is used to refer to the battery module of an energy storage device.

[0168] The average current of the first step-up / step-down inductor during the sampling period is taken as the first sampling inductor current, denoted as I. L1 The average current of the second step-up / step-down inductor during the sampling period is taken as the second sampling inductor current, denoted as I. L2 .

[0169] It should be noted that "L1" represents the first buck-boost inductor; "L2" represents the second buck-boost inductor.

[0170] To determine whether the first and second photovoltaic modules are cross-connected, two conditions must be met.

[0171] One of the judgment conditions is whether the absolute value of the difference between the converted inductor current and the sampled inductor current of this channel is greater than the first preset threshold.

[0172] Another criterion: whether the absolute value of the difference between the converted inductor current of the other path and the sampled inductor current of this path is less than the second preset threshold.

[0173] The input current is converted to inductor current, and the conversion relationship is as follows:

[0174] D pv1 =min(U bat / U pv1 ,1);

[0175] D pv2 =min(U bat / U pv2 ,1);

[0176] I L1_temp =I pv1 ×D pv1 ;

[0177] I L2_temp =I pv2 ×D pv2 ;

[0178] I L3_temp = I pv2 ×D pv1 ;

[0179] I L4_temp = I pv1 ×D pv2 .

[0180] Among them, D pv1 D represents the output duty cycle of the first photovoltaic DC-DC converter; pv2 This indicates the output duty cycle of the second photovoltaic DC-DC converter. (D) pv1 Corresponding to the duty cycle of the bridge arm connected to the first photovoltaic module; D pv2 This corresponds to the duty cycle of the bridge arm connected to the second photovoltaic module. (D) pv1 and D pv2 The maximum value is 1.

[0181] “min” means to take the minimum value. “U bat / U pv1 ” and “U bat / U pv2 "All of these represent the first ratio."

[0182] I L1_temp I L2_temp I L3_temp and I L4_tempBoth represent the converted inductor current. I L1_temp and I L2_temp Specifically, this represents the converted inductor current of this circuit; I L3_temp and I L4_temp Specifically, it represents the converted inductor current.

[0183] One of the judgment conditions is: |I L1_temp -I L1 |>I th1 ,|I L2_temp -I L2 |>I th1 I th1 This indicates the first preset threshold.

[0184] Another condition for judgment is: |I L3_temp -I L1 | th2 ,|I L4_temp -I L2 | th2 I th2 This indicates the second preset threshold.

[0185] If both of the above conditions are met simultaneously, and the duration of these conditions is greater than or equal to a preset time, a cross-connection error is determined to exist at the photovoltaic connection terminals, and the cross-connection error fault information is reported to the control platform (energy storage management cloud platform) or user terminal. For example, if both of the above conditions are met simultaneously, the cross-connection error fault information is reported after 2 seconds.

[0186] In some embodiments, optionally, such as Figure 5 and Figure 6 As shown, there are multiple second photovoltaic DC converters 112 and multiple second photovoltaic panels 130. The second photovoltaic positive terminal 1121 of each second photovoltaic DC converter 112 is connected to the second positive terminal 131 of a corresponding second photovoltaic panel 130.

[0187] Figure 5 This indicates that when there are multiple second photovoltaic DC converters 112 and multiple second photovoltaic panels 130, each photovoltaic panel (including the first photovoltaic panel 120 and the second photovoltaic panel 130) is normally connected to a corresponding photovoltaic DC converter (including the first photovoltaic DC converter 111 and the second photovoltaic DC converter 112) (there is no cross-connection error).

[0188] Figure 6 ​​This indicates that when there are multiple second photovoltaic DC converters 112 and multiple second photovoltaic panels 130, one of the second photovoltaic DC converters 112 is incorrectly connected to the first photovoltaic panel 120, and one of the second photovoltaic panels 130 is incorrectly connected to the first photovoltaic DC converter 111.

[0189] In some embodiments, optionally, such as Figure 8 As shown, obtaining the second converted inductor current and the second sampled inductor current includes:

[0190] S2042, obtain the second calculated inductor current and the second sampled inductor current corresponding to each second photovoltaic DC converter.

[0191] When there are multiple second photovoltaic DC converters and multiple second photovoltaic panels, the second converted inductor current and the second sampled inductor current corresponding to each second photovoltaic DC converter are obtained so that in subsequent steps, each second converted inductor current is compared with the first sampled inductor current to check whether there is any cross-connection error and the location of the cross-connection error.

[0192] In some embodiments, optionally, if the absolute value of the difference between the first converted inductor current and the first sampled inductor current is greater than a first preset threshold, and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is less than a second preset threshold, it is determined that a cross-connection error has occurred at the negative terminal of the photovoltaic panel, including:

[0193] S2062, sequentially taking each second photovoltaic DC converter as the current second photovoltaic DC converter, if the absolute value of the difference between the first calculated inductor current and the first sampled inductor current is greater than the first preset threshold, and the absolute value of the difference between the second calculated inductor current and the first sampled inductor current corresponding to the current second photovoltaic DC converter is less than the second preset threshold, it is determined that a cross-connection of the negative terminal of the photovoltaic panel has occurred between the first photovoltaic DC converter and the current second photovoltaic DC converter.

[0194] When there are multiple photovoltaic panels, comparing the current of each second converted inductor with the current of the first sampled inductor helps to accurately identify whether there is cross-connection error and the location of the cross-connection error.

[0195] The first calculated inductor current is compared with the first sampled inductor current to determine if a cross-connection error has occurred. Each second calculated inductor current is compared with the first sampled inductor current to simultaneously determine the presence and location of the cross-connection error. This design allows staff or users to quickly and accurately determine whether a cross-connection error has occurred on the negative terminal of the photovoltaic panel and its location, thus reducing workload and the possibility of missed detections.

[0196] In one embodiment of the present invention, the photovoltaic connection terminal cross-connection detection device 300 is applied to the energy storage device 110.

[0197] like Figure 15 As shown, the photovoltaic connection terminal cross-connection error detection device 300 includes a first current acquisition unit 310, a second current acquisition unit 320, and a cross-connection error determination unit 330.

[0198] The first current acquisition unit 310 is used to acquire the first converted inductor current and the first sampled inductor current. The first converted inductor current is obtained by converting the first input current of the first photovoltaic negative electrode device terminal 1112 through the first conversion relationship. The first sampled inductor current is the average current of the first step-up / step-down inductor 1113 during the sampling period.

[0199] It should be noted that if the sampling point of the photovoltaic input current is set at the negative terminal of the photovoltaic panel (the negative terminal of the panel), regardless of whether there is a cross-connection or not, the sampling current at the negative terminal of the photovoltaic panel will always be the "output current of this photovoltaic circuit", and it will not be able to report wiring errors.

[0200] In non-isolated photovoltaic (PV) systems, multiple PV DC-DC converters are grounded together, and therefore, their negative terminals (PV negative electrode terminals) are interconnected. By placing the PV input current sampling point at the negative terminal (PV negative electrode terminal) of the PV DC-DC converter, the input current of the PV panel that is incorrectly connected to this PV DC-DC converter can be sampled.

[0201] By setting the sampling point of the photovoltaic input current at the negative terminal (photovoltaic negative electrode terminal) of the photovoltaic DC converter, under the dual conditions of incorrect cross-connection of photovoltaic terminals and multiple photovoltaic DC converters sharing a common ground, the sampled current is naturally the input current of the photovoltaic panel that is incorrectly cross-connected with this photovoltaic DC converter. This detection method is beneficial for accurately and efficiently detecting incorrect cross-connection of photovoltaics.

[0202] By acquiring the first sampled inductor current and the first converted inductor current, it is convenient to compare the first sampled inductor current and the first converted inductor current in subsequent steps to determine whether a cross-connection of the negative terminal of the photovoltaic panel has occurred.

[0203] It should be noted that the first sampling inductor current is used as the sampling inductor current of this channel, and the first converted inductor current is used as the converted inductor current of this channel.

[0204] Optionally, the average current of the first buck-boost inductor 1113 during the sampling period is used as the first sampling inductor current. The first converted inductor current is determined based on the first input current and the first conversion relationship.

[0205] In one specific embodiment, the first converted inductor current is calculated by multiplying the sampled input current of the first photovoltaic panel 120 (the first input current of the first photovoltaic negative electrode device terminal 1112) with the output duty cycle of the first photovoltaic DC converter 111.

[0206] Once the photovoltaic DC / DC (Direct Current to Direct Current) converter is operating stably, there is a corresponding conversion relationship between the inductor current and the input current.

[0207] Taking a four-switch photovoltaic converter (a specific form of photovoltaic DC converter) as an example, the input current is multiplied by the corresponding output duty cycle (bridge arm duty cycle) to calculate the converted inductor current. Theoretically, the converted inductor current is equal to the average value of the sampled inductor current over the same period.

[0208] The second current acquisition unit 320 is used to acquire the second converted inductor current and the second sampled inductor current. The second converted inductor current is obtained by converting the second input current of the second photovoltaic negative electrode device terminal 1122 through the first conversion relationship. The second sampled inductor current is the average current of the second step-up / step-down inductor 1123 during the sampling period.

[0209] It should be noted that the second sampling inductor current is used as the other sampling inductor current, and the second converted inductor current is also used as the other converted inductor current. When there are multiple second photovoltaic DC-DC converters 112 and multiple second photovoltaic panels 130, the second converted inductor current and the second sampling inductor current corresponding to each second photovoltaic DC-DC converter 112 are obtained. In subsequent steps, each second converted inductor current is compared with the first sampling inductor current to check for any cross-connection errors and their locations.

[0210] Optionally, the average current of the second buck-boost inductor 1123 during the sampling period is used as the second sampling inductor current. The second converted inductor current is determined based on the second input current and the second conversion relationship.

[0211] The second converted inductor current is calculated by multiplying the sampled input current of the second photovoltaic panel 130 (the second input current of the second photovoltaic negative electrode terminal 1122) with the output duty cycle of the first photovoltaic DC converter 111.

[0212] The cross-connection determination unit 330 is used to determine that a cross-connection of the negative terminals of the photovoltaic panel has occurred if the absolute value of the difference between the first converted inductor current and the first sampled inductor current is greater than a first preset threshold and the absolute value of the difference between the second converted inductor current and the first sampled inductor current is less than a second preset threshold. The cross-connection of the negative terminals of the photovoltaic panel is that the first negative terminal 122 of the first photovoltaic panel 120 is mistakenly connected to the second negative terminal 1122 of the photovoltaic device, and the second negative terminal 132 of the second photovoltaic panel 130 is mistakenly connected to the first negative terminal 1112 of the photovoltaic device.

[0213] The converted inductor current (first converted inductor current) of this channel is compared with the sampled inductor current (first sampled inductor current) of this channel. The comparison result is used as one of the judgment conditions to determine whether cross-connection has occurred. Considering the actual sampling and calculation deviations, a first preset threshold is set. If the absolute value of the difference between the converted inductor current and the sampled inductor current of this channel is greater than the first preset threshold, it is initially judged that cross-connection may exist.

[0214] The comparison between the converted inductor current of the other path (second converted inductor current) and the sampled inductor current of this path (first sampled inductor current) is used as another judgment condition to determine whether cross-connection has occurred and to investigate the location of cross-connection errors. Considering the actual sampling and calculation deviations, a second preset threshold is set. If the absolute value of the difference between the converted inductor current of the other path and the sampled inductor current of this path is less than the second preset threshold, it is determined that cross-connection errors exist.

[0215] This invention aims to provide a detection device 300 for cross-connection errors of photovoltaic (PV) connection terminals. Based on a first sampling inductor current (local sampling inductor current), a first converted inductor current (local converted inductor current), and a second converted inductor current (other converted inductor current), it determines whether a cross-connection error has occurred on the negative terminal of the PV panel. This detection method has several advantages. First, it can promptly and accurately determine whether a cross-connection error has occurred on the negative terminal of the PV panel and the location of the error, reducing the workload of staff / users and the possibility of missed detections, thus improving detection efficiency and the accuracy of the results. Second, it can effectively detect cross-connection errors of PV connection terminals without increasing hardware costs, which helps control detection costs. Third, by accurately and efficiently detecting cross-connection errors of PV connection terminals, it can effectively avoid serious deviations in the acquisition of PV input current, ensuring that the maximum power point tracking function of the PV system does not fail, so that the PV panel operates at its optimal power generation efficiency point, which is beneficial to improving the utilization efficiency of solar energy; it can also effectively avoid the formation of unexpected electrical coupling between PV DC converters, which is beneficial to improving the service life of related electronic components and ensuring the long-term stable operation of the energy storage device 110.

[0216] In one embodiment of the present invention, such as Figure 16 As shown, the electronic device 400 includes a memory 410 and a processor 420. The memory 410 stores programs or instructions that can be executed on the processor 420. When the processor 420 executes the programs or instructions, it implements the steps of the photovoltaic connection terminal cross-connection detection method in any of the above embodiments. The electronic device 400 has the beneficial effects of any of the above embodiments, which will not be elaborated further here.

[0217] In this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0218] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0219] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0220] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting a cross-connection of a photovoltaic connection terminal, characterized in that, The application is applied to an energy storage device, the energy storage device comprises a first photovoltaic DC converter and a second photovoltaic DC converter, the first photovoltaic DC converter is connected with a first photovoltaic positive device terminal and a first photovoltaic negative device terminal, the first photovoltaic positive device terminal is used for connecting a first plate end positive terminal of a first photovoltaic panel, and the first photovoltaic DC converter comprises a first buck-boost inductor; the second photovoltaic DC converter is connected with a second photovoltaic positive device terminal and a second photovoltaic negative device terminal, the second photovoltaic positive device terminal is used for connecting a second plate end positive terminal of a second photovoltaic panel, and the second photovoltaic DC converter comprises a second buck-boost inductor; The detection method comprises: obtaining a first converted inductor current and a first sampled inductor current, the first converted inductor current is converted from a first input current of the first photovoltaic negative device terminal through a first conversion relationship, and the first sampled inductor current is an average current of the first buck-boost inductor in a sampling period; obtaining a second converted inductor current and a second sampled inductor current, the second converted inductor current is converted from a second input current of the second photovoltaic negative device terminal through the first conversion relationship, and the second sampled inductor current is an average current of the second buck-boost inductor in the sampling period; if an absolute value of a difference between the first converted inductor current and the first sampled inductor current is greater than a first preset threshold value, and an absolute value of a difference between the second converted inductor current and the first sampled inductor current is less than a second preset threshold value, it is determined that a photovoltaic panel negative terminal cross-connection error occurs; wherein the photovoltaic panel negative terminal cross-connection error is that a first plate end negative terminal of the first photovoltaic panel is connected to the second photovoltaic negative device terminal by mistake, and a second plate end negative terminal of the second photovoltaic panel is connected to the first photovoltaic negative device terminal by mistake.

2. The method of claim 1, wherein the method further comprises: After it is determined that the photovoltaic panel negative terminal cross-connection error occurs, the detection method further comprises: sending cross-connection error fault information to an energy storage management cloud platform, so that the energy storage management cloud platform sends cross-connection error prompt information to a user terminal based on the cross-connection error fault information, or sends the cross-connection error fault information to the user terminal through a short-distance wireless communication mode.

3. The method of claim 1, wherein the method further comprises: The energy storage device further comprises a first indicator lamp and a second indicator lamp; wherein the first indicator lamp is arranged at the first photovoltaic negative device terminal, and the second indicator lamp is arranged at the second photovoltaic negative device terminal; After it is determined that the photovoltaic panel negative terminal cross-connection error occurs, the detection method further comprises: controlling the first indicator lamp and the second indicator lamp to emit light or flash.

4. The method of claim 1, wherein the method further comprises: The energy storage device further comprises a voice prompt module; After it is determined that the photovoltaic panel negative terminal cross-connection error occurs, the detection method further comprises: controlling the voice prompt module to broadcast cross-connection error fault information.

5. The method of claim 1, wherein the method further comprises: The energy storage device further comprises a battery module, and output ends of the first photovoltaic DC converter and the second photovoltaic DC converter are connected to the battery module; The detection method further comprises: obtaining a first photovoltaic input voltage of an input end of the first photovoltaic DC converter, and a battery voltage of the battery module connected with an output end of the first photovoltaic DC converter; determining a first bridge arm duty cycle of the first photovoltaic DC converter at a side close to the first photovoltaic panel according to a ratio of the battery voltage and the first photovoltaic input voltage; determining the first conversion relationship according to the first bridge arm duty cycle.

6. The method of claim 1 to 5, wherein If the absolute value of the difference between the first conversion inductor current and the first sampling inductor current is greater than a first preset threshold value, and the absolute value of the difference between the second conversion inductor current and the first sampling inductor current is less than a second preset threshold value, it is determined that the negative terminal of the photovoltaic panel is crossed and connected by mistake, including: If the absolute value of the difference between the first conversion inductor current and the first sampling inductor current is greater than the first preset threshold value within a preset time, and the absolute value of the difference between the second conversion inductor current and the first sampling inductor current is less than the second preset threshold value within the preset time, it is determined that the negative terminal of the photovoltaic panel is crossed and connected by mistake.

7. The method of claim 6, wherein the method further comprises: The first preset threshold value is 1A to 3A; and / or the second preset threshold value is 1A to 3A; and / or the preset time is 1s to 3s.

8. The method of claim 1, wherein the method further comprises: The number of the second photovoltaic DC converters is multiple, and the number of the second photovoltaic panels is multiple, the second panel positive terminal of each of the second photovoltaic panels is connected with the second photovoltaic positive device terminal of a corresponding second photovoltaic DC converter; The method for obtaining the second conversion inductor current and the second sampling inductor current includes: obtaining the second conversion inductor current and the second sampling inductor current corresponding to each of the second photovoltaic DC converters; If the absolute value of the difference between the first conversion inductor current and the first sampling inductor current is greater than the first preset threshold value, and the absolute value of the difference between the second conversion inductor current and the first sampling inductor current is less than the second preset threshold value, it is determined that the negative terminal of the photovoltaic panel is crossed and connected by mistake, including: If the absolute value of the difference between the first conversion inductor current and the first sampling inductor current is greater than the first preset threshold value, and the absolute value of the difference between the second conversion inductor current and the first sampling inductor current is less than the second preset threshold value, it is determined that the negative terminal of the photovoltaic panel is crossed and connected by mistake, including:

9. A photovoltaic connection terminal cross-connection detection device, characterized by, The first current obtaining unit is configured to obtain a first conversion inductor current and a first sampling inductor current, the first conversion inductor current being converted from a first input current of a first photovoltaic negative device terminal through a first conversion relationship, and the first sampling inductor current being an average current of a first boost-buck inductor in a sampling period. ​ The second current acquisition unit is configured to acquire a second conversion inductance current and a second sampling inductance current, the second conversion inductance current being converted from a second input current of a second photovoltaic negative electrode device terminal through a first conversion relationship, and the second sampling inductance current being an average current of the second boost-buck inductance in a sampling period. The cross-wrong connection judgment unit is configured to, if an absolute value of a difference between the first conversion inductance current and the first sampling inductance current is greater than a first preset threshold value, and an absolute value of a difference between the second conversion inductance current and the first sampling inductance current is less than a second preset threshold value, determine that a photovoltaic panel negative electrode terminal cross-wrong connection occurs, wherein the photovoltaic panel negative electrode terminal cross-wrong connection is that a first panel end negative electrode terminal of a first photovoltaic panel is wrongly connected to the second photovoltaic negative electrode device terminal, and a second panel end negative electrode terminal of a second photovoltaic panel is wrongly connected to the first photovoltaic negative electrode device terminal.

10. An electronic device, comprising: The method comprises the following steps: A memory and a processor, wherein the memory stores a program or instructions executable on the processor, and the processor executes the program or the instructions to implement the steps of the photovoltaic connection terminal cross-wrong connection detection method in any one of claims 1 to 8.

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